Explanation of Names Spinipes probably refers to the extra spines on the front tibia compared to other members of the genus. Range worldwide, but by far most diverse in the Neotropics Remarks in some species the sexes are quite different in form and color, the female often brownish or red, the males black.
Habitat larvae live gregariously in the top layers of soil and leaf litter, rotten wood, and dung; adults often found on flowers Food larvae feed on leaf and needle litter, decaying organic matter, also on subterranean structures of live plants; Hesperinus larvae are xylophagous and bore in the decaying wood of various deciduous trees; adults apparently feed on nectar or pollen, but also on honeydew and plant liquids associated with damage from other insect feeding. adult Plecia do not feed. Life Cycle Adults emerge synchronously in huge numbers and often form dense mating aggregations. Males form loose "swarms" and copulate immediately with females as they emerge from the soil. After mating, female bibionines dig a small chamber in the soil with their fossorial fore tibiae, lay eggs, and die within the chamber (Plecia lay eggs on the soil surface). Adults are short-lived (3-7 days).Remarks larvae may damage cereal crops, vegetable crops, ornamental plants, nursery stock, grass, and forage crops; adult Bibio and Dilophus may be important pollinators in orchards and are the exclusive pollinators of some species of Orchidaceae and Iridaceae
